This proposal requests funds for an international conference on Hematopoietic Stem Cells. The symposium will comprehensively review recent developmental, cellular, genetic and molecular developments in the field of normal and neoplastic hematopoietic stem cell differentiation. Our specific aim is to gather and attract a workshop of over 150 scientists and clinicians who are of international repute or who are in the formative years of their careers for the purpose of presenting, discussing and exchanging conceptual information, techniques and ideas concerning the molecular biology, immunobiology and membrane biochemistry of hematopoietic stem cells. Our hope is to identify potentially fertile areas of basic research that may serve to guide future research endeavors. The proceedings of the symposium will be published in a monograph whose purpose is to stimulate the continued development of this field that was pioneered by Dr. Frederick Stohlman, Jr. The five-day conference will be composed of workshops that will address: (1) models and mechanisms of stem cell differentiation; (2) growth factors and regulators of stem cell differentiation; (3) biochemical alterations of erythroid cell membranes during differentiation; (4) genetic control of hematopoiesis; and (5) growth and regulation of neoplastic hematopoietic stem cell growth. In addition, poster sessions will provide the opportunity for young investigators to present data relevant to each of these topics. Our long-term objective is to provide an opportunity for the presentation of recent advances in basic cell biology together with those in classic stem cell physiology in order to explore new approaches to obtain a better understanding of how normal and malignant cell proliferation occur.